Final answer:
The gas price rose by 5%.
Step-by-step explanation:
To calculate the percentage increase in price, we can use the formula:
Percentage increase = ((New price - Old price) / Old price) * 100%
Substituting the given values, we have:
Percentage increase = ((3.15 - 3.00) / 3.00) * 100% = 0.15 / 3.00 * 100% = 5%
Therefore, the gas price rose by 5%.